LICINIUS I (Valerius Licinianus Licinius)
- Licinius was born c. 265 in the province of Dacia Nova.
- To sort out the problems of the rival claimants to the imperial throne(s), Diocletian was briefly brought out of retirement in November 308 for an imperial conference at Carnuntum near Vienna. The result was a new tetrarchy. Licinius, another Illyrian army officer and friend of Galerius, was appointed Augustus in the west, in place of Severus. Constantine and Maximinus Daia were given the title of filius Augusti, Maxentius, who had usurped power in Italy in 306, was declared a public enemy and Maximian, whom Maxentius had created co-ruler, was forced to resign. Under pressure from Constantine and Maximinus, Galerius promoted them to full Augustii, early in 309.
- Licinius, based at Sirmium, was now challenging Maxentius for control of Italy and North Africa, and he made some small gains in 309.
- On 30th April 311, Galerius died, leaving Licinius and Maximinus Daia fighting for control of the east.
- On 28th October 312, Constantine defeated Maxentius at the battle of the Milvian Bridge, near Rome.
- In 313, Licinius allied himself to Constantine by marrying his half-sister Constantia. Licinius and Constantine issued the Edict of Milan in 313, which granted religious toleration.
- Meanwhile, Maximinus had crossed the Bosphorus into Europe to confront Licinius.
- On 30th April 313 they joined in battle on the plain of the River Ergenus, near Hadrianopolis. Licinius won against superior odds.
- Licinius and Constantine now shared the Empire between them.
- In 316, Constantine proposed that his brother-in-law, Bassianus, be appointed Caesar in Italy. Licinius refused, so Constantine invaded the Balkans.
- On 8th October 316, Constantine defeated Licinius's army at the battle of Cibalae.
- Licinius fled to Serdica where he proclaimed one of his commanders, Valens, as his partner in power.
- Valens's army met Constantine's at a second battle of Hadrianopolis, a place called Campus Ardiensis. The result was not decisive and Constantine was forced to come to terms.
- A treaty was signed at Serdica on 1st March 317. The unfortunate Valens was executed. Constantine's sons Crispus and Flavius Claudius Constantinus (Constantine II)were proclaimed Caesars, as was Licinius junior.
- Licinius, although not rabidly anti-Christian, was not a believer himself. When he suspected certain bishops of disloyalty, he had them executed. This gave Constantine all the excuse he needed.
- The two met again at Hadrianopolis, where Constantine gained the victory - 3rd July 324.
- Licinius fled across the Bosphorus and appointed another unfortunate, Martius Martinianus, as his co-ruler.
- Constantine followed and again defeated Licinius at Chrysopolis on 18th September 324.
- Licinius and Martinianus surrendered at Nicomedia on condition their lives were spared. They were, but not for long. Both later were killed together with the 9 year old Licinius junior.